The present invention is related to an improved magnetic material fixing structure of motor rotor. The rotor includes multiple overlapping silicon steel plates. Each silicon steel plate is formed multiple receptacles on outer circumference. Each receptacle has multiple resilient plates for resiliently tightly clamping and firmly fixing the magnetic material.
A conventional motor rotor is composed of multiple overlapping silicon steel plates. The circumference of each silicon steel plate is formed with multiple recesses at equal intervals. Each recess has a dimension slightly larger than a magnetic material, whereby the magnetic material can be painted with an adhesive and then inlaid and fixed therein.
After a period of use, the adhered magnetic material tends to detach from the silicon steel plate in high speed operation of the motor.
In order to solve the above problem, the magnetic material can be embedded in the silicon steel plate. Please refer to FIGS. 4 and 5. In another type of conventional motor rotor, the silicon steel plate 8 is formed with a central fixing hole 81 for a central shaft to pass therethrough. The outer circumference of each silicon steel plate 8 is formed with multiple through holes 82 at equal intervals. A magnetic material 9 is tightly fitted and fixedly embedded in the through hole 82.
In order to firmly fix the magnetic material 9 in the through hole 82, the through hole 82 is designed with a dimension smaller than that of the magnetic material 9. However, the magnetic material 9 is made of cracky material so that when forcedly pressed and embedded in the through hole 82, the magnetic material 9 is subject to cracking. This leads to a defective product.
Moreover, after embedded, the magnetic material 9 is tightly engaged with the periphery of the through hole 82. Therefore, the heat generated by the magnetic material 9 in operation of the rotor is not easy to radiate. The increased temperature will lead to decrement of magnetic energy of the magnetic material 9. In addition, a distance between the through hole 82 and the outer circumference of the silicon steel plate 8 is necessary for having sufficient strength to fix the magnetic material 9. However, this distance elongates the distance between the magnetic material 9 and the locator 91 around the rotor. Accordingly, the air gap H between the magnetic material 9 and the locator 91 is enlarged. This will lead to decrement of torque of the motor.
It is therefore a primary object of the present invention to provide an improved magnetic material fixing structure of motor rotor. An outer circumference of each silicon steel plate of the rotor is recessed to form multiple receptacles. Each receptacle has multiple resilient plates. When inlaying the magnetic material in the receptacle, the resilient plates are deformed to resiliently evenly tightly clamp the magnetic material so as to firmly fix the magnetic material.
It is a further object of the present invention to provide the above fixing structure in which when inlaying the magnetic material into the receptacle, the respective resilient plates are deformed to enlarge the receptacle, whereby it is easy to tightly fit and inlaid the magnetic material into the receptacle without damaging the magnetic material.
It is still a further object of the present invention to provide the above fixing structure in which after inlaid in the receptacle, the magnetic material is closer to the locator to reduce the air gap between the magnetic material and the locator. This increases the torque of the motor in operation.
It is a further object of the present invention to provide the above fixing structure in which the receptacle is divided by dented sections to form multiple resilient plates. Therefore, when the magnetic material is embedded in the receptacle and clamped by the resilient plates, the dented sections serve as ventilation passages for enhancing the heat-radiating efficiency of the magnetic material in operation of the motor. Moreover, a portion of the magnetic material at the opening of the receptacle is directly exposed to the air of the air gap between the rotor and locator. Therefore, the heat can be more easily dissipated so as to reduce the negative effect of the magnetic material caused by the heat.
The present invention can be best understood through the following description and accompanying drawings wherein: